Systems and methods for pulsed posterior vitreous detachment creation

ABSTRACT

This disclosure relates to a tissue separation system to separate the posterior vitreous cortex from the inner limiting membrane in the eye, and to the separation of other body tissues. A system includes a flexible elongate member having a proximal end and a distal end. The flexible elongate member is coupled to a fluid reservoir and has a lumen configured to deliver fluid from the reservoir for use in a surgical procedure and further includes a pump system coupled to the proximal end of the flexible elongate member and to the fluid reservoir, configured to pressurize the fluid to a pressure suitable for separating tissues. The system also includes a control system arranged to control the pump system to provide a series of pulses of fluid through the flexible elongate member and out from the distal end thereof to suitably separate the tissues during the surgical procedure.

TECHNICAL FIELD

The present disclosure relates to apparatuses and methods for ophthalmicmedical procedures, and more particularly, to apparatuses and methodsincluding separation of the vitreous humor from the retina.

BACKGROUND

Many microsurgical procedures require precision cutting, removal, and/orseparation of various body tissues. For example, certain ophthalmicsurgical procedures require the cutting and/or removal of the vitreoushumor, a transparent jelly-like material that fills the posteriorsegment of the eye. The vitreous humor, or vitreous, is composed ofnumerous microscopic fibrils that are often attached to the retina bythe posterior vitreous cortex. Therefore, cutting and removal of thevitreous must be done with great care to avoid traction on the retina,the separation of the retina from the retinal pigment epithelium, aretinal tear, or, in the worst case, retinal detachment. Delicateoperations such as mobile tissue management (e.g., cutting and removalof vitreous near a detached portion of the retina or a retinal tear),vitreous base dissection, and cutting and removal of membranes areparticularly difficult.

With age, the vitreous may naturally contract and separate from theretina and, generally, this occurs without negatively affecting thevision or health of a person's eyes. However, in some instances thevitreous may detach from some portions of the retina without detachingfrom others. This may cause a contracting vitreous to pull on theretina, distorting vision and potentially causing a tear also called aretina break, potentially leading to retinal detachment. Otherconditions such as vitreomacular traction, resulting from thevitreomacular adhesion and vitreomacular schisis are a result ofincomplete separation of the vitreous humor from the posterior retina.The condition may be treated by attempting to mechanically detach theadhered portion of the vitreous from the retina.

Detaching adherent vitreous can be accomplished using standardvitrectomy probes. These typically include a hollow needle with a porton the end to pull in fibrils forming the vitreous humor. An innermember, placed within the hollow needle, moves back and forth to openand close the port. This operates to cut any fibrils that enter the portwhile it is open. The motion used to position vitreous within the hollowneedle may be a back and force motion tangential to the surface of theretina that places significant sheer stress on the delicate retinathrough the posterior vitreous cortex. Another approach relies onenzymes to chemically separate the vitreous from the retina. While thisapproach may be effective, it may also generate unwanted side effects.Accordingly, the current approaches are not satisfactory in allrespects.

SUMMARY

This disclosure relates generally to, and encompasses, systems andmethods for separating one layer of body tissue from another, such asseparating a posterior vitreous cortex from the inner limiting membrane(ILM), and more specifically to ophthalmic surgical systems and methodsof using the systems to generate posterior vitreous detachment sites toalleviate vitreomacular adhesion (VMA) and treat vitreomacular traction.Separation of the vitreous from the retina is also required to treatsome types of retinal detachment typically in younger, near-sightedpatients and trauma patients.

According to one example, this disclosure relates to a tissue separationsystem that may include a flexible elongate member having a proximal endand a distal end. The flexible elongate member may be coupled to a fluidreservoir and may have a lumen configured to deliver fluid from thereservoir for use in a surgical procedure. The tissue separation systemmay further include a pump system coupled to the proximal end of theflexible elongate member and to the fluid reservoir, and may beconfigured to pressurize the fluid to a pressure suitable for separatinga first body tissue from a second body tissue. The tissue separationsystem also may include a control system in communication with the pumpsystem. The control system may be arranged to control the pump system toprovide a series of pulses of fluid through the flexible elongate memberand out from the distal end of the flexible elongate member to suitablyseparate the first body tissue from the second body tissue during thesurgical procedure.

According to another example, an ophthalmic surgical system forposterior vitreous detachment is described. The surgical system mayinclude a handpiece that may have a flexible elongate member with aproximal end and a nozzle at a distal end. The proximal end may beconfigured to couple to a fluid reservoir for use in a surgicalprocedure. And the nozzle may be arranged to emit fluid in a manner thatseparates a first body tissue from a second body tissue. The surgicalsystem may include a pump system coupled to the proximal end of theflexible elongate member and to the fluid reservoir and may include acontrol system in communication with the pump system. The control systemmay cause the pump system to provide a series of pulses of fluid throughthe flexible elongate member, the series of pulses being expelled fromthe nozzle of the flexible elongate member to separate the first bodytissue from the second body tissue.

According to yet another example, a method of performing a surgery thatmay include receiving a command from a user of a surgical system toinitiate a detachment process, forcing a first pulse of fluid from afluid reservoir of the surgical system through a lumen of a flexibleelongate member in a handpiece to a surgical site to separate a firstbody tissue from a second body tissue, and forcing a second pulse offluid from the reservoir of the surgical system through the lumen to thesurgical site to further separate a first body tissue from a second bodytissue, is disclosed.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory innature and are intended to provide an understanding of the presentdisclosure without limiting the scope of the present disclosure. In thatregard, additional aspects, features, and advantages of the presentdisclosure will be apparent to one skilled in the art from the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate embodiments of the devices andmethods disclosed herein and together with the description, serve toexplain the principles of the present disclosure.

FIG. 1A is a cross-sectional illustration of an eye of a patient.

FIG. 1B is a cross-sectional illustration of a normal portion of theretina of the eye.

FIG. 1C is a cross-sectional illustration of a symptomatic portion ofthe retina of the eye shown in FIG. 1.

FIG. 2 is an illustration of an exemplary surgical system according toaspects implementing the teachings and principles described herein.

FIG. 3 is a diagram of a surgical probe with a flexible elongate memberfor insertion into the eye of a patient according to one example ofprinciples described herein.

FIG. 4 is a functional diagram illustrating some of the components ofthe surgical system according to aspects of the present disclosureimplementing the teachings and principles described herein.

FIGS. 5A, 5B, and 5C are three views of a distal end of the flexibleelongate member of the surgical probe illustrated in FIG. 3 according toone example incorporating the principles described herein.

FIGS. 5D, 5E, and 5F are three views of a distal end of the flexibleelongate member of the surgical probe illustrated in FIG. 3 according toanother example incorporating the principles described herein.

FIGS. 6A, 6B, and 6C are three views of a distal end of the flexibleelongate member of the surgical probe illustrated in FIG. 3 according toanother example incorporating the principles described herein.

FIGS. 7A, 7B, and 7C are three views of a distal end of the flexibleelongate member of the surgical probe illustrated in FIG. 3 according toanother example incorporating the principles described herein.

FIG. 8 is a flowchart showing an illustrative method for performing asurgery to separate tissues according to one example incorporating theprinciples described herein.

FIG. 9 is a diagram of an exemplary surgical procedure utilizing asurgical system according to one example of principles described herein.

FIG. 10 is a flowchart showing another illustrative method forperforming a surgery to separate tissues according to one exampleincorporating the principles described herein.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the disclosure is intended. Any alterations and furthermodifications to the described systems, devices, instruments, methods,and any further application of the principles of the present disclosureare fully contemplated as would normally occur to one skilled in the artto which the disclosure relates. In particular, it is fully contemplatedthat the features, components, and/or steps described with respect toone embodiment may be combined with the features, components, and/orsteps described with respect to other embodiments of the presentdisclosure. For simplicity, in some instances the same reference numbersare used throughout the drawings to refer to the same or like parts.

The present disclosure relates to devices, systems, and methods forseparating tissues, particularly ocular tissues, and more particularlyadhered layers of tissues. The various figures show embodiments ofexemplary ophthalmic surgical systems and devices and methods of usingthe devices to separate delicate tissues within a patient's eye.Embodiments described herein incorporate pulsed fluid aspects of asystem that may operate to cause separation of the vitreous from theretina during a procedure to treat vitreomacular traction, vitreomacularschisis or retinal detachment, which if left untreated may result invision distortion or vision loss. One of ordinary skill in the art,however, would understand that similar embodiments could be used toseparate delicate tissues in other locations in the body withoutdeparting from the general intent or teachings of the presentdisclosure.

FIG. 1A is a cross-sectional illustration of an eye 100. A number offeatures of the eye 100 are illustrated herein. The eye 100 includes asclera 102 that is coupled to a retinal membrane or retina 104 by achoroid. The choroid includes the retinal pigment epithelium to attachthe retina 104 to the inside wall of the sclera 102 at the back of theeye 100 and to provide oxygen and nourishment to the outer layers of theretina 104. A cornea 108 permits light to enter the eye 100, the lightbeing focused by a lens 110 through a vitreous chamber onto the retina104, which contains photo-activated cells that transmit signals over theoptic nerve 106 to the brain. The vitreous chamber is filled withvitreous humor 112 or, simply, vitreous 112 that includes a cleargelatinous hyaluronan material including collagen fibers distributedtherein. The vitreous 112 is in contact with the innermost layer of theretina 104.

FIG. 1B illustrates in greater detail an area of interest 114 of the eye100. FIG. 1B shows an eye 100 in a normal condition in close-up toprovide greater, schematic detail of the tissue layers of the retina104. The laminated or layered tissues present in the eye 100 are notdrawn to scale. As shown in FIGS. 1A and 1B, the retina 104 includesseveral layers, including a main retinal layer 120, a sub-retinal space122, and an opaque layer 124. The retinal layer 120 includes an innerlimiting membrane (ILM) 126 that is in contact with the posteriorvitreous cortex 128 of the vitreous humor 112 that fills the vitreouschamber. The retinal layer 120 further includes a nerve fiber sub-layer,a ganglion cell sub-layer, an inner plexiform sub-layer, an innernuclear sub-layer, an outer plexiform sub-layer, and an outer nuclearsub-layer. The retinal layer 120 also includes an external limitingmembrane and a photoreceptor sub-layer. The opaque layer 124 includesthe retinal pigment epithelium (RPE) and the choroid.

As shown in FIG. 1B, the posterior vitreous cortex 128 is in continuouscontact with the ILM 126. However, in human eyes it is common for thevitreous 112 to decouple or detach from the retina as age increases.However, in some instances the detachment may be not complete, such thata portion of the vitreous 112 may adhere to the retina 104 even whilethe vitreous 112 contracts, as is shown in the area of interest 114 ofthe eye 100 of FIG. 1C. When this occurs, the contraction of thevitreous 112 exerts a force 130 on the retina 104. This force may causethe retina 104 to bend unnaturally, as shown in FIG. 1C, or to tear insome cases. Accordingly, there is a desire to be able to detach thevitreous 112 from the retina 104 to prevent damage to the retina 104 andto prevent associated visual distortion and/or loss of sight.

FIG. 2 illustrates an exemplary ophthalmic surgical system, shown as aconsole 200. The console 200 includes a base housing 202 with acontroller or computing subsystem 204 and an associated display screen206 adapted to show data relating to system operation and performanceduring a posterior vitreous detachment (PVD) procedure. The console 200also includes a number of subsystems that may be used together toperform surgical procedure to separate one body tissue from another,such as separating the vitreous 112 from the retina 104 of FIG. 1. Forexample, the subsystems may include one or more of a foot pedalsubsystem 208 including a foot pedal 210 having a number offoot-actuated controls and a fluidics subsystem 212 including ahand-held surgical separation device shown as hand piece 214. The handpiece 214 may include components that allow a clinician to direct aseries of pulses of fluid to a surgical site near the posterior of theeye to separate adhered tissues.

In some embodiments, the console 200 further includes an ultrasonicgenerator subsystem within the housing 202 that is operable to cause aphacoemulsification tip of a hand piece to oscillate ultrasonically.Some embodiments of the console 200 further include a pneumaticvitrectomy cutter subsystem with a vitrectomy hand piece. The pneumaticvitrectomy cutter subsystem may be coupled to or be part of the fluidicssubsystem 212 to provide pressurized air to power the vitrectomy handpiece.

The fluidics subsystem 212 may include one or more reservoirs of fluidthat may be used in a surgical procedure. As illustrated in FIG. 2, theconsole 200 includes a reservoir 216. The reservoir 216 may contain afluid to be injected into the eye or another part of the body in aseries of pulses. In some embodiments, the fluid in the reservoir 216 isair and the reservoir 216 is a tank of compressed gas. In otherembodiments, the reservoir 216 may contain a balanced salt solution(BSS), a perfluorocarbon liquid such as perfluoro-n-octane (PFO),hydroxypropyl methylcellulose (HPMC), hyaluronic acid, chondroitinsulfate, or another viscoelastic. The fluid in the reservoir 216 may bea non-Newtonian, pseudoplastic, viscoelastic fluid, in some embodiments.Additionally, the reservoir 216 may contain air. Some embodiments of thefluidics subsystem 212 may include other reservoirs in addition to thereservoir 216. For example, the fluidics subsystem 212 may include apump or a compressor that is controlled by the computing subsystem 204to generate a series of pulses of one or more fluids contained incorresponding one or more reservoirs. The fluidics subsystem 212provides for the control of pressure and/or volume of fluids expelledfrom the fluidics subsystem 212.

These subsystems of console 200 may overlap, in some embodiments, andcooperate to perform various aspects of a procedure and may be operableseparately and/or independently from each other during one or moreprocedures. That is, some procedures may utilize one or more subsystemswhile excluding others.

FIG. 3 is a stylized diagram showing a portion of the illustrativetissue separation hand piece 214. According to the present example, thehand piece 214 includes a body 302 and a flexible elongate member 304having a lumen therethrough through which a fluid may pass toward adistal end 306. The body 302 forms a handle portion that may be graspedand manipulated by a surgeon when performing a surgical procedure, suchas a posterior vitreous detachment (PVD) procedure. In some embodiments,the exterior portion of the body 302 is ergonomically designed forcomfortable grasping by the surgeon. The body 302 may be made from avariety of materials commonly used to form such tools. For example, thebody 302 may be made of, for example, a lightweight aluminum, a polymersuch as polyether ether ketone (PEEK), or another material. Depending onthe embodiment, it may be sterilized and used in more than one surgicalprocedure, or it may be a single-use device.

In the illustrated embodiment, the distal end 306 of the flexibleelongate member 304 includes a tapered section with a nozzle portion 308that may be used to direct the fluid as it is ejected under pressurefrom the flexible elongate member 304. The flexible elongate member 304may be a flexible cannula sized for insertion into the eye of a patientthrough a surgical opening therein. The body 302 is coupled to theflexible elongate member 304 such that the distal end 306 thereof may bemanipulated by a clinician by manipulating the body 302. In someembodiments, the flexible elongate member 304 includes a pre-formed bendat the distal end.

The body 302 may include one or more buttons, knobs, or other physicalinterface elements to permit the clinician to adjust certain aspects ofthe performance of the surgical system 200. As illustrated, the body 302includes a toggle switch or button 310 that may be used to start andstop a series of pulses of fluid being emitted from the nozzle portion308. The body 302 further includes a slider 312 that permits theclinician to adjust at least one characteristic of individual pulses orof the series of pulses between two extreme positions. For example, theslider 312 may control a volume of each of the pulses of fluid between100 microliters and 10 microliters. Other volume amounts or ranges maybe used in other embodiments, and higher and lower volumes arecontemplated. In other embodiments, the slider 312 controls the pressureat which the fluid is ejected from the nozzle portion 308. For example,a maximum pressure may be 30 pounds per square inch (PSI) in someembodiments. In general, the pressure of the fluid may be inverselyproportional to the viscoelasticity of the fluid injected by the handpiece 214 into the eye of the patient. Accordingly, a pressure of 30 PSImay be more appropriate when the fluid injected is viscoelastic. In someembodiments, the slider 312 may control the rate of the series ofpulses, such that the clinician may be able to increase or decrease thepulsation rate. Other embodiments of the hand piece 214 may includesliders or other physical interface elements for each of these functionsand more. Additionally, in some embodiments, the console 200 may providephysical user interface elements or virtual user interface elementswhereby the clinician or an assistant may control characteristics of theindividual pulses or the series of pulses.

In other embodiments, the control of each pulse or series of pulses interms of pulse volume, pulse pressure, pulse frequency, pulse duration,etc. may be controlled individually or collectively by the foot pedalsubsystem 208. Specific characteristics of an individual pulse or seriesof pulses may be controlled by one or more footswitches like thefootswitch 210. Additionally, a graphical user interface (GUI) may beprovided by the console 200, and a clinician may provide user controlsto control pulse characteristics and may start and stop generation ofpulses using the foot pedal subsystem 208 in connection with the GUI.For example, characteristics of the pulse or pulses may be set oradjusted by interaction with the GUI and the starting and stopping ofpulses may be controlled by the footswitch 210.

Within the body 302, the lumen of the flexible elongate member 304connects to a conduit 314 that couples the hand piece 214 to thefluidics subsystem 212 of the surgical system 200 of FIG. 2. The conduit314 may include a flexible elongate member that couples the flexibleelongate member 304 to the reservoir 216 or to another reservoir or to apump system coupled to one or more reservoirs. Additionally, the conduit314 includes electrical connections between the button 310 and theslider 312 on the body 302 to the computing system 204. In someembodiments, commands to adjust the pressure, volume, and rate of theseries of pulses may be received by the clinician's manipulation of thefoot pedal subsystem 208 rather than, or in addition to, commands issuedvia the components of the hand piece 214.

Referring now to FIG. 4 shown therein is a diagram of a fluidicssubsystem 400 that may be included in embodiments of the console 200 asthe fluidics subsystem 212. As illustrated, the fluidics subsystem 400includes a pump system 402 that is coupled to a reservoir 404A and to areservoir 404B. The pump system 402 removes fluid from one of thereservoirs 404A and 404B for injection into the eye of the patientthrough the flexible elongate member 304 as described herein. Thefluidics subsystem 400 further includes a control system 406 that iselectronically and communicatively coupled to the pump system 402 and toa plurality of valves incorporated into the fluidics subsystem 400. Insome embodiments, the control system 406 may be provided by thecomputing system 204 of FIG. 2 and may provide electrical signals toopen and close the plurality of valves and/or to control a pump withinthe pump system 402. In some embodiments, the pump system 402 includes adiaphragm pump or peristaltic pump; other embodiments may include othertypes of pumps as may be apparent to one of skill in the art. Forexample, the control system 406 may receive a command from the handpiece 214 to increase the pressure provided by the pump system 402. Thecontrol system 406 may interpret the command from the hand piece 214 andprovide the appropriate signals to the pump system 402 to increase thepulse pressure.

In some embodiments of the fluidics subsystem 400, one or morecomponents may be provided in the hand piece 214. For example, the pumpsystem 402 and the control system 406 may be provided within the body302. In such embodiments, the body 302 may include one or more internalreservoirs. The internal reservoirs may be filled and replenished fromthe reservoirs 404A and/or 404B. The pump system 402 may pull fluid fromthe reservoirs 404A and 404B and force the fluid out of the body 302,through the flexible elongate member 304, under a desired pressure at adesired rate in pulses containing a desired volume per pulse.

In some embodiments of the fluidics subsystem 400, one of the reservoirs404A and 404B includes a dye that may be combined with another fluid tomake that other fluid visible when injected into the patient to separatetissues. For example, the reservoir 404A may include a balanced saltsolution while the reservoir 404B includes a visible dye. The fluidicssubsystem 400 may be configured to mix fluids from both the reservoir404A and the reservoir 404B prior to injection into the patient in aseries of pulses. In some embodiments, the fluid injected into thepatient may include an active chemical or biological component, such asan enzyme, that reacts with a feature at the surgical site. For example,in some embodiments the fluid injected in a series of pulses includesocriplasmin, a protease that can dissolve the proteins that secure thevitreous 112 to the retina 104. In such embodiments, the series ofpulses creates a posterior vitreous detachment through the applicationof pressure and through an enzymatic reaction. Other chemical orbiological components may be used in other embodiments.

Referring now to FIGS. 5A, 5B, and 5C, shown therein are three views ofa nozzle portion 500 of a flexible elongate member such as the flexibleelongate member 304 of FIG. 3. In some embodiments of the surgicalsystem described herein, a nozzle is included at the distal end of theflexible elongate member 304 in order to more effectively direct thefluid as it is injected into the eye of a patient to separate one tissuefrom another. FIG. 5A is an “end on” view that depicts an opening 502 inthe nozzle portion 500, which has an enlarged, spatula-like shape. Theopening 502 is depicted as being generally oval in shape and having awidth W1 and a height H1. In some embodiments, the opening 502 and othersuch slit-like openings described herein, may have an ellipticalopening, a rectangular opening, or an opening having another shape. Theshape may be symmetric or asymmetric relative to the width and/or heightof the opening. Additionally, some embodiments may include a pluralityof openings. While, as illustrated, the width W1 is greater than thediameter of the flexible elongate member (including the thickness of theflexible elongate member and the diameter of the lumen therethrough),the height H1 is less than the diameter of the flexible elongate member.This may be seen in the top view of the nozzle portion 500 as shown inFIG. 5B and in the cross-sectional side view of FIG. 5C, respectively.The cross-sectional side view of FIG. 5C is viewed along the line 5C-5Cof FIG. 5B.

Referring now to FIGS. 5D, 5E, and 5F, shown therein are three views ofa nozzle portion 550 of a flexible elongate member such as the flexibleelongate member 304 of FIG. 3. The nozzle portion 550 is similar to thenozzle portion 550 in many respected. While the nozzle portion 500 isconfigured to direct fluid along the luminal axis of the flexibleelongate member, the nozzle portion 550 directs fluid away from theluminal axis at an angle θ. By directing the nozzle portion 550 at theangle θ in a direction D1, rather than along the luminal axis L1, thefluid may be directed slightly away from the ILM 126 and the rest of theretina 104. In this way, damage to the retina 104 during posteriorvitreous detachment may be further minimized. FIG. 5D is an “end on”view that depicts an opening 552 in the nozzle portion 550, which has anenlarged, spatula-like shape. The opening 552 is depicted as beinggenerally oval in shape and having a width W1 and a height H1, betterobserved in the cross-sectional view of FIG. 5E. In other embodiments,the nozzle portion 550 may curve away from the luminal axis L1. Thecurve or angle at which embodiments of the nozzle portion 550 directsthe fluid away from the luminal axis may range from about 10° to about60° or more. The cross-sectional side view of FIG. 5C is viewed alongthe line 5C-5C of FIG. 5B.

Shown in FIGS. 6A, 6B, and 6C is a nozzle portion 600 that may beincluded at the distal end of the flexible elongate member to beinserted into the eye of a patient to facilitate in carefully separatingthe vitreous 112 from the retina 104 with minimal tearing or stressingof the retina 104. The nozzle portion 600 is similar in many respects tothe nozzle portion 500; however, the nozzle portion 600 includes twoopenings rather than one. The nozzle portion 600 includes a side port602 on an upper side and a side port 604 on the lower side of a distaltip of the nozzle portion 600. In some embodiments, additional sideports may be present. As illustrated, the side ports 602 and 604 directfluid away from the distal end of the flexible elongate member indirections that are off the central, lengthwise axis L1 of the flexibleelongate member 304. Depending on the orientation of the flexibleelongate member and its positioning proximate the retina 104 and thevitreous 112, one of the side ports directs fluid toward the retina 104while the other side port directs fluid toward the vitreous 112. In someembodiments, one of the side ports may direct fluid along the axis L1,while the other side port directs fluid away from axis L1 at an angle asshown in FIGS. 5C, 5D, and 5E. FIG. 6A provides an end on view of thenozzle portion 600, while FIG. 6B provides a top view thereof. FIG. 6Cis a cross-sectional view of the nozzle portion 600 as seen according tothe line 6C-6C of FIG. 6B.

Referring now to FIGS. 7A, 7B, and 7C, shown therein is yet anotherembodiment of a distal end of the flexible elongate member. The nozzleportion 700 includes an opening 702 having a width W2 and a height H2.The nozzle portion 700 is similar to the nozzle portion 500 in manyrespects. However, the width W2 is not greater than the diameter of theflexible elongate member. A top view is included in FIG. 7B, while across-sectional view is presented in FIG. 7C according to the line 7C-7Cof FIG. 7B.

The nozzle portions 500, 550, 600, and 700 present only a fewembodiments of the nozzle 308 of FIG. 3, and aspects may be combined invarious embodiments. In some embodiments, the opening or openings mayhave a different shape, such as a rectangular shape, and there may bemore than two openings. In some embodiments, the nozzles may be made ofa polymer or a metal alloy such as nitinol. Some embodiments of thenozzles 600 and 700 may be configured, like the nozzle 550, to directfluid away from the luminal axis of the flexible elongate member 304, inorder to prevent damage to the retina 104. In general, the nozzleportions 500, 550, 600 and 700 direct the fluid injected in a series ofpulses that separate the posterior vitreous cortex 128 from the ILM 126in order to prevent damage to the retina 104.

Referring now to FIG. 8, shown therein is a flowchart of a method 800for performing a surgical procedure to separate tissues, such as aposterior vitreous cortex from an ILM. As shown in FIG. 8, the method800 includes several elements or operations. Embodiments of the method800 may include additional elements or operations before, after, inbetween, and/or as part of the enumerated elements. The elements of themethod 800 may be performed by a surgical system, such as the surgicalsystem 200 of FIG. 2 and as described herein.

In the performance of an exemplary method 800, a clinician may make asmall opening in the posterior vitreous cortex with a surgicalinstrument, such as a curved tip, flexible cannula. The cannula may befurther configured to direct a series of pulses of fluid injected inbetween the posterior vitreous cortex and the ILM. In other embodiments,a second surgical instrument is used to provide the series of pulsesafter the opening is made. Once the surgical instrument capable ofdirecting pulses of fluid to the interface between the posteriorvitreous cortex and the ILM is in place, the clinician may use a buttonon a hand piece, such as the hand piece 214, or a foot pedal, such asthe foot pedal 210 to direct a surgical system to initiate a posteriorvitreous detachment creation process.

At 802, a control system receives a command from the user to initiatethe posterior vitreous detachment process. This command may be receivedby the control system from the user when the user manipulates a switchor other physical interface element. The control system may be thecomputing subsystem 204 of the console 200, illustrated in FIG. 2 or thecontrol system 406 of FIG. 4. The computing subsystem 204 includes aplurality of subcomponents in order to receive, process, and issuecommands to control a series of pulses to separate tissues. The controlsystem includes one or more processing devices, such as centralprocessors or microcontrollers. The processing devices may be present inmultiple components of the console 200. For example, the console mayinclude a first processing device and the hand piece 214 may include asecond processing device.

The control system interprets the received command and directs, at 804,a pump system to force, expel, or inject a first pulse of fluid from afluid reservoir through a flexible elongate member to a surgical sitewithin the patient, such as at a posterior portion of the eye of thepatient. For example, the control system 406 may include amicrocontroller that directs the pump system 402 to generate a pulse offluid. As directed, the pump system 402 may actuate a diaphragm pump, aperistaltic pump, or another type of pump, and cause fluid in the pumpto be expelled through the flexible elongate member 304 of the handpiece 214, and into the eye of the patient. Depending on the pump system402, the pulse of fluid may correspond to a single pump cycle. Forexample, when the pump system includes a diaphragm pump, a single pulsemay be provided by a single pump cycle. In such embodiments, controllingaspects of the pulse may be provided by adjusting a pump volume,adjusting a pump frequency, adjusting a pump force, etc. The pump system402 may include one or more valves to ensure that the first pulse offluid is injected into the eye rather than drain from the eye. In someother embodiments, the pump system 402 provides a source of continuouspressure that is released in a series of pulses by actuating a valve togenerate the series of pulses of fluid.

FIG. 9 is a diagram of an exemplary surgical procedure utilizing asurgical system according to one example of the principles describedherein to illustrate the application of a pulse of fluid as describedherein. FIG. 9 is similar in many respects to FIGS. 1B and 1C, showingvitreous 112 being detached from the retina 104. As shown in FIG. 9, aflexible elongate member 304 is inserted between the posterior vitreouscortex 128 and the ILM 126. When a pump system is activated by controlsystem to force a pulse of fluid 902 (or pulse 902) out of the nozzleportion 308, the pulse 902 produces a pressure against the vitreous 112and the retina 104 to separate these two tissues. Because the fluid doesnot have hard or sharp edges, the pulse 902 may minimize potentialdamage to the retina 104. The fluid may also distribute the force alonga greater area. Thus, the use of fluid may provide a safer approach toposterior vitreous detachment creation than current methods that rely ona vitreous cutter to perform a vitrectomy that can expose the retina totangential forces. The pressure applied by the pulse 902 may becontrolled by the selection of the fluid and/or by control of the pumpsystem 402. For example, when the pulse 902 is a pulse of air the pumpsystem 402 may be set to provide a higher pressure than when the pulse902 is a non-Newtonian fluid.

When the fluid includes an enzyme such as ocriplasmin, or another suchactive component, both the enzyme and the application of pressure may beused to separate the two tissues. In such embodiments, the rate ofpulsation and/or other aspects of the series of pulses may be adjustedto accommodate the chemically or biologically active component. Forexample, a pressure may be decreased in view of the concentration of theactive component in the fluid. Additionally, in some embodiments therate of pulsation may be decreased as active components are included inthe fluid and/or the concentration of such active components isincreased. Because the application of pressure is also relied upon toseparate the tissues, the concentration and/or quantity of activecomponent may be less than that required when only the active componentis relied upon to separate the tissues. In instances in which the activecomponent may produce unwanted side effects, the combination of theapplication of a series of pulses as described herein may decrease theproduction of such side effects.

Referring again to FIG. 8, after the first pulse of fluid is forced tothe surgical site, at 806, a second pulse of fluid may be forced throughthe flexible elongate member to the surgical site within the patient.Between 804 and 806, the clinician may advance the flexible elongatemember to better position the nozzle portion 308. For example, theinjection of the first pulse of fluid into the eye of the patient mayincrease an area of detachment between the vitreous 112 and the retina104 (i.e., may increase the posterior vitreous detachment). In order toincrease the efficiency of any subsequent pulses, the clinician mayadvance the nozzle portion 308 closer to regions of maintainedattachment. In some embodiments, the position of the nozzle portion 308may be maintained for more than one pulse before the nozzle portion 308is advanced.

In this manner, a series of pulses may be injected into the eye of thepatient between the posterior vitreous cortex 128 and the ILM 126. Thepressure of the series of pulses may cause the posterior vitreous cortex128 and the ILM 126 to separate without applying shear stress to theretina 104. This may increase the safety and efficacy of posteriorvitreous detachment creation as described herein.

Referring now to FIG. 10, shown therein is a flowchart of a method 1000according to some aspects of the present disclosure. While the method1000 is illustrated as having elements or operations, embodiments of themethod 1000 may include additional elements before, after, in between,and/or as sub-elements of the enumerated elements.

As illustrated in FIG. 10, the method 1000 may begin at 1002 in whichdistal end of a surgical separation device is inserted into a posteriorsegment of the eye. As part of the insertion into the eye, a smallfenestration or cut may be made in the vitreous cortex to permit aportion of the surgical separation device to be inserted between theposterior vitreous cortex and the ILM.

After the surgical separation device is positioned between the vitreousand the retina of the eye, at 1004, a fluid is pulsed in a series ofpulses from the distal end of separation device to separate the firsttissue from the second tissue. The series of pulses may each applypressure between the first and second tissues to separate them withoutapplying substantial shear stress that may damage either of the twotissues. The series of pulses may be provided in response to a requestfrom a user to initiate the series. For example, the user may be aclinician using a surgical system (such as the surgical system 200 ofFIG. 2). The clinician may use the foot pedal 210 or may use anotherinterface provided on a hand piece, like the hand piece 214. At 1006,the separation device is removed from the segment of the eye.

Principles described herein can provide several benefits to surgicaloperations involving the separation of one tissue layer bound togetherwith another tissue layer. For example, use of the series of pulsesrather than a mechanical cutting tool limits potential cutting damage toeither tissue. The series of pulses can also separate tissue efficientlywithout subjecting the retina to significant shear stresses, which cancause tearing of the retina. The separation device described herein mayalso provide for more effective use of active component that dissolvethe fibers connecting the layers of tissues.

Persons of ordinary skill in the art will appreciate that theembodiments encompassed by the present disclosure are not limited to theparticular exemplary embodiments described above. In that regard,although illustrative embodiments have been shown and described, a widerange of modification, change, and substitution is contemplated in theforegoing disclosure. Similarly, while examples provided herein may bedirected to separating the vitreous from the retina in an eye, theprinciples of the present disclosure may be applicable to separate otheradhered bodily tissues in a safe, effective manner. It is understoodthat such variations may be made to the foregoing without departing fromthe scope of the present disclosure. Accordingly, it is appropriate thatthe appended claims be construed broadly and in a manner consistent withthe present disclosure.

What is claimed is:
 1. A posterior vitreous detachment system,comprising: a flexible elongate member having a proximal end and adistal end, the flexible elongate member being coupled to a fluidreservoir and having a lumen configured to deliver fluid from thereservoir for use in a posterior vitreous detachment procedure; a pumpsystem coupled to the proximal end of the flexible elongate member andto the fluid reservoir, the pump system configured to pressurize thefluid to a pressure suitable for separating vitreous from a retina; anda control system in communication with the pump system, the controlsystem being arranged to control the pump system to provide a series ofpulses of fluid through the flexible elongate member and out from thedistal end of the flexible elongate member to suitably separate thevitreous from the retina during the posterior vitreous detachmentprocedure.
 2. The tissue separation system of claim 1, furthercomprising a tapered section at the distal end of the flexible elongatemember, the tapered section comprising a nozzle through which the pulsesare expelled from the distal end.
 3. The tissue separation system ofclaim 1, wherein the distal end comprises a first side port and a secondside portion, the first side port directing the series of pulses towardthe vitreous and the second side port directing the series of pulsestoward the retina.
 4. The tissue separation system of claim 1, furthercomprising a nozzle configured to direct the series of pulses of fluidaway from a luminal axis of the flexible elongate member.
 5. The tissueseparation system of claim 1, wherein the fluid reservoir containspressurized air and the pump system comprises a valve that releases apulse of pressurized air.
 6. The tissue separation system of claim 1,wherein the pump system comprises a diaphragm pump.
 7. The tissueseparation system of claim 1, further comprising a footswitch actuatableto initiate the series of pulses.
 8. The tissue separation system ofclaim 7, wherein the controller encodes the user command to cause thecontrol system to: initiate the series of pulses; terminate the seriesof pulses; adjust a pressure of the series of pulses; or adjust a volumeof fluid expelled in each pulse of the series of pulses.
 9. The tissueseparation system of claim 1, wherein the fluid reservoir contains anon-Newtonian fluid.
 10. The tissue separation system of claim 1,wherein the fluid comprises a balanced salt solution.
 11. An ophthalmicsurgical system for posterior vitreous detachment, the surgical systemcomprising: a handpiece comprising a flexible elongate member having aproximal end and a nozzle at a distal end, the proximal end beingconfigured to couple to a fluid reservoir for use in a surgicalprocedure, the nozzle at the distal end being arranged to emit fluid ina manner that separates a vitreous from a retina; a pump system coupledto the proximal end of the flexible elongate member and to the fluidreservoir; and a control system in communication with the pump system,the control system causing the pump system to provide a series of pulsesof fluid through the flexible elongate member, the series of pulsesbeing expelled from the nozzle of the flexible elongate member toseparate the vitreous from the retina.
 12. The ophthalmic surgicalsystem of claim 11, wherein a width of the nozzle is greater than adiameter of the flexible elongate member.
 13. The ophthalmic surgicalsystem of claim 11, further comprising an interface element incommunication with the control system, the interface element configuredto receive a command from a user and to transmit the command to thecontrol system.
 14. The ophthalmic surgical system of claim 11, whereinthe fluid reservoir contains an enzyme.
 15. The ophthalmic surgicalsystem of claim 11, wherein the pump system is further coupled to asecond reservoir containing a second fluid.
 16. A method of performing aposterior vitreous detachment, the method comprising: receiving acommand from a user of a surgical system to initiate a detachmentprocess; forcing a first pulse of fluid from a fluid reservoir of thesurgical system through a lumen of a flexible elongate member in ahandpiece to a surgical site to separate a vitreous from a retina; andforcing a second pulse of fluid from the reservoir of the surgicalsystem through the lumen to the surgical site to further separate thevitreous tissue from the retina.
 17. The method of claim 16, wherein thefirst pulse of fluid contains one of: air; salt solution;perfluoro-n-octane; or a viscoelastic polymer.
 18. The method of claim16, wherein the first pulse of fluid has a volume of about 100microliters or less.
 19. The method of claim 16, further comprising:receiving a first selection from the user that indicates a pulse volume;and receiving a second selection from the user that indicates a pulsepressure, and wherein the first pulse of fluid has the pulse volume andwherein forcing the first pulse of fluid comprises forcing the firstpulse of fluid at the pulse pressure.
 20. The method of claim 16,wherein the first pulse and the second pulse are forced through aflexible elongate member having a proximal end and a nozzle at a distalend, the flexible elongate member being coupled to the fluid reservoir.